Metal reducing method



Aug. 1l, 1936. s 1 EvERr-:TT

METAL REDUCING METHOD Filed April 19, 1935 vwd?,

Patented Aug. 11, 1936 acetate Marsi, anatema rm'rnon Samuel JamesEverett, London, England, as

signor to Thos. Firth & John Brown limited, Sheiieid, England, a Britishcompany v Application April i9, 1935. Serial No. 17,316

lin Great Britain April 25, i934 Y is creams.' (ci, 20s- 21) Thisinvention relates to processes for reducing metal rods, wires, stripsand the like by dra ing, rolling and analogous operations.

The invention is concerned with a process of the type in which aplurality of elements (rods, Wires, strips or the like) each of which isto be reduced as aforesaid, is made up as a bundle, i. e. inside-by-side relationship held together, for example -by an encasingtube or binding, and

then subjected, i. e. as a unit, to drawing, rolling or analogousoperations. The present invention provides a process for the productionof fine wires by reduction from elements of larger cross section, whichcomprises the steps of assembling a plurality of said elements inside-by-side relationship, enclosing the assembly of elements in atubular casing, inserting a packing material within the casing, reducingthe bundle thus formed as a unit and then removing the casing' andpacking material and separating the individual reduced wires.

The term matrix as used in this specification is intended to mean asupport for the surfaces of the indivdual Velements oi the bundle whichdistributes pressure applied to the outside of the encasing tubesubstantially evenly-over the surfaces of the individual elements eitherthroughout the reduction process, or at least during apart of thatprocess, and thereby assists in limiting any distortion of the shape ofthe elements. The matrix may be formed, for example, by employing alarge proportion (e. g. 22% by volume) of packing of a pulverulent orplastic nature, by so shaping the individual elements that they form asupport for one another, by embedding the elements in metallic packingintroduced into the encasing tube or binding in molten form, or byencasing each of the elements in individual tubes of a material which,during reduction, will readily deform to fill up the interstices in theassembled bundle. When the elements are so shaped as to form their ownmatrix they may be arranged to t together without interstices and mayall be of similar cross-section and conform to a regular straight-sidedpolygon-e. g. a square or a hexagon.

.According to another feature of the invention, and for the purpose offacilitating the separation of the encasing tube after the reductionprocess has been completed, the bundle may be bound helically with awire or the like prior to insertion in the encasing tube, so that in theassembly the inner'surface of the tube will be separated vfrom thebundle by the binding wire.

Some examples embodying features of the invention will now be describedwith reference to the accompanying diagrams, in which:-

Figure 1 is a cross-section showing a bundle oi. rods of circularcross-section in an encasing tube;

Figure 2 is a section showing the deformation 5 in the section of theindividual rods after reduction;

Figure 3 is a cross-section showing one method of providing a matrixaccording to the invention;

4Figure 4 shows an alternative form of matrix; 10

Figure 5 shows another form of the invention in which the matrix for oneelement is formed by the contiguous sides of adjacent elements;

Figure 6 is a view illustrating the use of a helical binding between thebundle and the en- 15 casing tube;

Figure 7 is a section illustrating a further example of the invention,and

Figure 8 is a section illustrating the application of the process to thereduction of sheets. 2o

Like reference numerals indicate like partsin the various figures.

In Figure l a number of rods i@ of circular cross-section are shownpacked in an encasing tube il. If a composite billet is made up in this25 way and subjected to reduction, for example by drawing or rolling,the radial compression will tend towards deformation in thecross-section oi the rods in directions towards the interstices asindicated in Figure 2. 'I'he nature and extent 30 of the distortionvaries somewhat according to the location of the individual elementswith respect to the circumference of the tube.

For the purpose of minimizing the degree of distortionthe invention,according to the ex- 35 ample shown in Figure 3, makes use of a packingmaterial of a pulverulent or plastic nature, such as French chalkor'metal in powdered form as a separating medium between the individualelements of the bundle. As shown, the rod-like 40 elements I 0 arelocated in separated relationship within an outer tube Il and theinterstices are completely iilled in by a packing I2 of the above kind.'Ihe packing l2 not only limits the degree of distortion of thesections, but prevents 45 the elements from becoming welded togetherduring reduction and thereby facilitates the splitting up of the bundlewhen the reducing process has been completed.

In the example shown in Figure 4 each rod- 50 like element I0 isseparately enclosed in a tubular -metal sheath I3, and all the elementsare then inserted in bundle form within an encasing tube H Here again amatrix is provided for each element.

of the bundle. Preferably the sheath I3 is of a 55 metal (e. g. copper)which is substantially more 'ductile than that of which the elements l@are ponent elements.

composed., so that during the initial stage or stages of the reductionprocess, the sheaths will be deformed to nil in the interstices in thestructure. If desired, a packing material in powdered form may also beused. In this example it will be appreciated that upon completion of thereduction process, and after the encasing tub-e ll has been removed,each element has to be separated ,from its protective sheath lil. Thiscan readily be done by dissolving with acid, the selection of the metalfor the sheath being made with this end in View. Alternatively if acoated wire is desired the sheath i3 may be left in position.

In the example illustrated in Figure 5 the individual elements l@ areall of hexagonal crosssection, so that they may be assembled, as shown,in intertting relationship, the matrix for each element being formed bythe contiguous faces of adjacent elements. The bundle is as beforeenclosed in an outer tube ll and a packing materia-l l2 is locatedbetween the periphery of the bundle and the inner wall of the encasingtube, This packing material may, for example, be French chalk, plasterof Paris or powdered metal, or molten metal may be run into the tube toform the packing. Further packing, such as French chalk, is alsointroduced between the adjacent faces of the individual elements inorder to assist in the final splitting up of the bundle into its com-This example of the invention may be carried out with bars of anydesired crosssection which interit to form a solid cross-section and theelements need not all be of the same cross-section. Thus rectangles oi"different dimensions may be used for the different elements or roundsections in conjunction with four-sided concave sided sections may beemployed. A further example is the combination with square sections oioctagonal sections.,

ln certain cases it may not be desirable or convenient to use a chemicalorlelectroiytic method of removing the encasing tube l l afterreduction, and in such cases the arrangement illustrated in Figure 6 mayadvantageously be employed. lite-- ferring to that figure the individualrods or wires l@ are made up in a bundle as before with a separatingmedium such as graphite between the individual elements, and the bundleprior to insertion in thev outer casing il is helically bound with ametal wire or strip lll. After reduction the tube l l may be cutlongitudinally by a machining operation without damaging the drawnelements, since the latter are protected byl the binding lll. After thetube il has been removed, the wire [bl can be unwound and the individualelements exposed. ln some cases where a helical binding is employed thismay entirely replace the outer encasing tube Il l, the bound bundlebeing subjected direct to the reducing operations.

In the arrangement shown in Figure l the individual rods are inserted inlongitudinal holes l5 drilled in a solid billet. ln this case theinterior portion ci? the billet constitutes the matrices for theindividual elements, and the circumferential portions taires the placeof the encasing tube l Il employed in the previous examples.

In the example shown in Figure 8 the invention is applied to thereduction by rolling or the like of individual elements l@ in the formof plates, slabs or the like. As before, these are assembled in the formof a bundle or pack with a separating medium l2 located between adjacentlayers. The pack is enclosed in a rectangular actuaba closed in. Asbefore, the separating medium may l be a metal, for example, where theplates lil are of carbon steel, the separating metal may be copper ornickel, or again a pulverulent or like packing such, for example, aspowdered (not iiaked) graphite, or metallic oxide may be used.

In any of the foregoing examples the encased bundle may be subjected tohot or cold working. Where the process is applied to the production ofne wires and the main consideration is to minimize any alteration in thecross-sectional shape of the wires, drawing through dies is thepreferred method of reduction. At intermediate stages between successivereduction stepsand/or as a iinal operation, annealing or other specialheat treatment may be necessary or' desirable, and in this connection itwill be appreciated that a process of the type with which the inventionis concerned offers substantial practical advantages n that it enables abatch of rods or the like undergoing reduction to be simultaneouslysubjected to the same heat treatment in the form of a' single unit whichcan be readily manipulated.

The outer binding or casing for the bundle need not necessarily be aseamless tube. For example, a tubular case with a longitudinal seemed orlapped joint may be used, a separatingy agentsuch, for example, aschromium oxide-being injacent elements may be constituted by an oxidelayer of substantial thickness, purposely formed at the surface oftheelements with this object in view. Again, an oxide layer may be usedin conjunction with the other forms of packing already described.

The processes described herein may be used for the reduction ofindividual elements lof any desired metal or alloy, and in each case theform and composition of the matrix and outer binding or case will beselected with dueregard to the method which is to be employed forseparating the individual elements after the nal reduction, thedesirability of minimizing distortion of the original section and otherfactors which have already been considered. In one example where theprocess was applied to the production of ne wires of stainless steelcontaining 18% chromium and 8% nickel, a copper matrix was used and anouter tubular casing of high carbon steel was fine wires.

A further alternative method of removing a high carbon steel outercasing is to bring it into a brittle state by heat-treatment and then tocrack it off the bundle.

Thepresent invention has many industrial applications, for example tothe manufacture of very For example, starting with nine round sectionwires of 0.65l mm. in diameter, and of stainless steel having thecomposition given above, encased in a tube it is readily possible by thepresent method to produce nal sections with a diameter approaching 0.002inch, and still of very nearly round section. p

In a further example eighty stainless steel or nichrome (80% Ni, 20% Cr)wires .65 mm. in diamete.` were each encased in separate copper tubesformed by pressing copper strip around the wires and were then packedinside a half inch diameter copper tube. The composite billet thusformed was then reduced by drawing (in another example by rolling) downto a diameter of .17 mm. The copper was then dissolved off leaving thewires which had a diametery of about 0.0004 inch.

Wires of this fine section may be spun into multiple iilament threads,and these may be woven into fabrics. Another application of theinvention is to the production of stranded wire, cable or the like.Stranded wire or cable may be produced by reducing a bound or encasedbundle of rods or Wires by the methods already described and thenimparting a helical twist to the reduced bundle and, where necessary,thermally treating the bundle to set the individual elements or strandsand/or to impart any desired physical properties. As before, theencasing tube, binding and matrix are finally removed by chemical,electrolytic or mechanical means. Ii desired, at one or (ach end of thereduced cable or multiple wire, the matrix, where it is of metal such ascopper, may be allowed to remain in position so as to form solid endportions which may be vuseful for threading, for instance Where thefinal product is a iine stranded wire which is to be Woven into afabric. Where a solid tube is employed for encasing the bundle, it may,if desired7 be recovered as a useful commercial product, i. e. aseamless drawn tube. If this end is in View, the composition of theenclosing tube will be selected with regard to the nature and propertiesof the material in the recovered tube. When the composite billet hasbeen reduced to the desired size, the tube may be freed from theenclosed elements by cross rolling or any other convenient method.

In the selection of packing material those materials which do not extenduniformly or which tend to bind under pressure (e. g. flake graphite orcoachfnlling) are found not to be so suitable as materials which extenduniformly under the pressure of rolling or drawing (e. g. metallicsubstances, French chalk or chromic oxide) It is within the invention toemploy the rcduced bundle in the production of a brush. In thisapplication a portion of the encasing tube is left in position to holdtogether the individual wires and form a handle for the brush.

l. A process for the production of stranded wire by reduction fromelements of comparatively large cross section which comprises the stepsof assembling a plurality cf said elements in side-by-side relationship,encasing the assembly of elements, reducing the bundle thus formed as aunit, imparting a permanent helical twist to the reduced bundle and thenremoving the casing.' l

2. A process for the production of ne wires, strips or the like byreduction from elements of larger cross section comprising the steps ofassembling a plurality of said elements in sideby-side relationship,encasing the assembly of elements in a tube of high carbon steel,inserting a packing material within the tube, reducing the bundle thusformed asa unit and then cracking oil the tube. 1

3. A process for the production of ilne Wires by reduction from solid`,elements of larger cross section, which comprises the steps ofassembling a plurality of said elements in side-by-side relationship,enclosing the assembly of elements in a tubular casing, inserting apacking material within the casing, reducing the bundle thus formed as aunit and then removing'the casing and packing material and separatingthe .individual reduced wires.

4. A process for the production of ne'wires by reduction from solidelements of larger cross section, which comprises assembling a pluralityof said elements in side-by-side relationship, enclosing the assembly ofelements in a tubular casing, providing a matrix for each individualelement, reducing the bundle thus formed as a unit and then removing thecasing and separating the individual wires.

5. A process for the production of ne wires by reduction fromsolidelements of larger cross vat least 22% of thevolume within thecasing,

reducing the bundle thus formed as a unit and then removing the casingand the packing material and separating the individual wires.

6. A process for the `production of ne wires by reduction from solidelements of larger cross section, which comprises employing elements ofcross sections which will fit together without interstices, assembling aplurality of said elements side-by-side in intertting relationshipwithout interstices, the sides of each element acting directly as amatrix for the contiguous sides of adjacent elements, enclosing theassembly of elements in a tubular casing, reducing the. bundle thusformed as a unit and then removing the casing and separating theindividual wires.

7. A process for the production of fine wires by reduction from solidelements of larger cross section which comprisesv employing elementswhereof the cross section bf' each is thesame and conforms to a regularstraight-sided polygon which will interfit without intestices with'contguo'us elements ,of the same cross section, assembling a pluralityof said elementsy in side-byside interiitting relationship, enclosingthe assembly of elements in a tubular casing, reducing the bundle thusformed as a unit and then removing the casing and separating theindividual wires.

8. A process for the production of fine Wires from solid elements oflarger cross section, which comprises the steps of assembling aplurality of said elements in side-by-side relationship, 'eni the innerwall of the casing with a packing material, reducing the bundle thusformed as a unit,

then removing the casing by dissolving with an acid, removing thepacking material and sep= arating the individual Wires.

9. A process for the production of une Wires by reduction from solidelements of larger cross section, which comprises the steps ofassembling a plurality of said elements vin side-by-side relationship,enclosing the assembly of elements in a tubular casing, running a moltenmetal packing into the casing to embed the elements, reducing the bundlethus formed as a unit and then removing the casingI and tbe metalpacking to separate the individual wires. l0. A process for tbeproduction oi due wires ci stainless steel by reductiontrorn solidelements of suoli material of larger cross section, which comprises tbesteps ot enclosing veacli element in a separate copper sheath,assembling a plurality of such sheathed elements in side-by-siderelationsliip, enclosing tbe assembly in a copper tube, reducing thebundle 'tinus formed as a unit and then removing the casing and tbeslieatiis by dis= solving oi the copper, and separating tlie reducedwires.

il. .l process for tne production ci une wires by reduction from solidelements of larger cross section, which comprises tbe steps ofassenibling a plurality ci said elements in side-bymside rela tionship,lielically binding the assembly, enclos ing the bound assembly in atubular casing, reg ducing the bundle tinus formed as a unit, rernov ingthe casing, unvvinding the lielical binding and separating tine reducedtvires.

i2. il process for tlieproduction oi tine 'Wires reductionirorn solidelements of larger cross section, which comprises tbe steps of forminglayers oi oxide ot substantial tl'iicliness on the surfaces o tbeelements, wsernbllng a plurality oi said oxidized elements insidembghside relationsnip, enclosing the assembly ot elements in atubular casing, reducing tire bundle tlius formed as a unit and thenremoving tire casing and sep arating tbe individual wires.

i3. An article oi manufacture comprising a aosoaoe exible metal librehaving a surface such as formed on metallic strands when elongated in abundle with other strands with a separating vmatrix and of such smallcross-sectional area that it may be spun into multiple-ment threads. v

1i, An article of manufacture comprising a flexible metal nbre ofthread-like length having a surface such. as formed on metallic strandswhen elongated in a bundle with other strands with a separating matrixand or across-sectional area such that the bres may be spun intomultiple-diametri; threadscapable of being Woven into exible fabrics.

l5; An article of manufacture comprising a exible metal' fibre ofthread-like length having a surface such as formed on metallic strandswhen elongated in a bundle vvitb other strands with a separating matrixand of a cross-sectional area such that the fibres maybe spun intomultiple-lament threads comparable in iieiubility to threads formed fromorganic fibres and capable of being woven into a iabric.,

i6. An article o manufacture comprising a fabric woven rom strandedmultiple-filament threads of metal, the threads being spun from metalfibres having a diameter oi an order ranging from 0.002 incn -to 0.0004inch and having a surface suoli as formed on metallic strands whenelongated in a bundle with other strands with a separating matrix. v

l?. .lin article oi manufacture comprising a lielically twisted cableconsisting of a bundle of flexible fibres off small cross-sectionalarea, all o vlbicli bres are reduced in cross-sectional .in a bundle. f

An article of manufacture comprising a flexible and ductile metal libreoi a diameter of an order ranging from 0.002 inclu to 0.0004 inclu andhaving a surface sucio. as formed on metallic strands 'when elongated ina bundle with other? strands with a separating matrix.,

SAMUEL JAR/DES

